The present invention relates to a process and an apparatus for forming a heat dissipating element such as a semi-conductor heat sink.
U.S. Pat. No. 4,879,891 issued to Hinshaw on Nov. 14, 1989 discloses a process for forming a semi-conductor heat sink by cross-cut gang sawing, in a transverse direction, a longitudinally extending profiled extruded metal member in order to enhance the heat dissipating efficiency of the heat sink. The extruded member comprises a longitudinally extending sheet-form member having a plurality of longitudinally extending and transversely spaced ribs positioned thereon. By cross-cut sawing the ribs depthwise in a transverse direction along a length thereof and then parting off a predetermined length from a processed portion of the extruded member, a semi-conductor heat sink comprising a base member having a plurality of transversely spaced rows of longitudinally extending rib portions is formed. With a ratio of the height of the ribs to the spacing dimension between the ribs of at least six to one, sharp burrs might be created on the sawn edges during cross-cutting of the ribs, which must be removed before the heat sink can be utilized. Furthermore, as illustrated in FIG. 6, the rib 53 first approached and sawn by a cutting tool 62 is apt to break at location 54.
U.S. Pat. No. 5,572,789 issued to Fisher et al. on Nov. 12, 1996 discloses a process for forming a profiled element from a longitudinally extending extruded member having a plurality of transversely spaced longitudinally extending ribs projecting therefrom. In this process, longitudinally extending, spaced apart portions are removed from at least some of the ribs by means of a transversely acting punching means to produce a profiled element in which the rib portions of adjacent ribs are staggered, i.e., not in transverse alignment.
The present invention aims to obviate the disadvantage of the above mentioned defects associated with the cross-cut gang sawing of ribs.